1. Field of the Invention
The present invention relates to a method for manufacturing a semiconductor device having a back-side gate electrode on the location facing the front-side gate electrode on the back face of the substrate.
2. Background Art
A transistor having a plurality of gate electrodes between a source electrode and a drain electrode in order to improve OFF characteristics has been proposed (for example, refer to Japanese Patent Laid-Open No. 2007-73815). For increasing the yield, it is necessary to ensure that the distance between the gate electrodes is a certain distance or more. Therefore, since the distance between the source electrode and the drain electrode is greater, the ON resistance is increased, voltage lowering occurs, output is lost, and the ON characteristics of the element are degraded. Thus, the ON characteristics and the OFF characteristics have been in a tradeoff relationship.
On the other hand, a transistor having a back-side gate electrode on the location facing the front-side gate electrode on the back face of the substrate has been proposed (for example, refer to Japanese Patent Laid-Open No. 9-82940). Thereby, the ON-OFF control of current can be performed from both the front side and the back-side, and the OFF characteristics are improved. In addition, since the distance between the source electrode and the drain electrode is not increased, the degrading of the ON characteristics can also be prevented.